Direct immobilization of laccase on titania nanoparticles from crude enzyme extracts of P. ostreatus culture for micro-pollutant degradation

Enzymatic treatment can effectively degrade recalcitrant micro-pollutants in wastewater. However, its industrial application is constrained by the high cost of the purified enzyme preparations. This work introduces a novel technique to directly immobilize the in-house crude enzyme extracts (from P. ostreatus) onto the functionalized TiO2 nanoparticle surface. Comprehensive investigations were carried out to understand the interactions between complex crude enzyme extracts and the immobilization support. By simple dilution of the crude enzyme extract, the immobilization efficiency can be significantly improved. The resultant biocatalytic nanoparticles had comparable performance to the immobilized purified commercial enzymes. Finally, the micropollutant degradation capability of the biocatalytic nanoparticles was demonstrated with two micro-pollutants, namely, bisphenol-A and carbamazepine, commonly detected in sewage. The efficient laccase extraction and immobilization on biocatalytic nanoparticles show great promise as a cost-effective alternative to conventional wastewater treatment processes for recalcitrant micro-pollutants. (C) 2017 Elsevier B.V. All rights reserved.